package singleton;

public class School {

    public static void main(String[] args) {
          Principal principal1 = Principal.getInstance();
          principal1.announcement("食堂阿姨手稳一点");

          Principal principal2 = Principal.getInstance();
          principal2.approveDocument("全校放假三天");

          boolean result = principal1==principal2;
          System.out.println(result);

    }
}
